Joystick

Description

The EVK1100 provides a joystick to design Human to Machine Interface for software developments.


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Pinout

The joystick inputs are low level active. (ie : the PVR register value is 0 when the joystick is set in a direction and/or pressed, and 1 otherwise)
The pinout is as follow :

Joystick Pin Joystick Direction GPIO Name Alternate function used
Joy_A LEFT PA 25 SCAN_0
Joy_B UP PA 26 SCAN_1
Joy_C DOWN PA 27 SCAN_2
Joy_D RIGHT PA 28 SCAN_3
EXTINT PUSH PA 20 EXTINT_8

see below the hardware schematic :

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Using Interrupts

In order to use the joystick, two ways are available :

  • Polling on the GPIO Port Value Register
  • Using GPIO interrupts to get state changes

Using GPIO interrupts need to :

  • Register an interrupt handler for the input (depending on the compiler you are using),
  • Set the GPIO control bit for the input,
  • Set the GPIO glitch filter bit for the input,
  • Configure the GPIO interrupt mask bit for the input to act either on rising edge, falling edge or input change (this mode should be the better for the joystick),
  • Set the GPIO interrupt enable bit for the input.


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